1. Field of the Invention
The present invention relates to a scroll compressor, and more particularly, to a scroll compressor capable of reducing a frictional force between parts by adjusting high pressure generated during the compressing process by means of the orbiting movement of an orbiting scroll in the scroll compressor.
2. Description of the Related Art
Generally, a scroll compressor is operated for compressing by means of relative movement of a fixed scroll and an orbiting scroll, and widely used in the fields of room air conditioners and automobile air conditioners owing to its advantageous characteristics such as high efficiency, low noise, small size and light weight.
The scroll compressor is classified into a low pressure scroll compressor and a high pressure scroll compressor according to the filling gas, namely whether an inhaling gas is filled in the casing or a discharging gas is filled therein, and the following description is based on the low pressure scroll compressor.
A scroll compressor generally includes a main frame, an Oldham ring seated on the upper surface of the main frame for linear movement, an orbiting scroll seated on the upper portion of the Oldham ring for orbiting movement, and a fixed scroll positioned at an upper portion of the orbiting scroll and fixed to the main frame. In addition, the fixed scroll has a fixed scroll wrap spirally twisted, and the orbiting scroll has an orbiting scroll wrap spirally twisted and formed on the upper surface thereof. In more detail, the fixed scroll wrap and the orbiting scroll wrap form a compressor chamber, and the fluid received in the compressor chamber is compressed by means of movement of the orbiting scroll.
FIG. 1 is a sectional view showing the compressing process accomplished in a general scroll compressor of the related art.
Referring to FIG. 1, the conventional scroll compressor includes a fixed scroll wrap 81 formed on the fixed scroll, an orbiting scroll wrap 71 formed on the upper surface of the orbiting scroll and inserted into the fixed scroll wrap 81 to form a compressor chamber P, and a discharge port 9 formed at the center of the orbiting scroll wrap 71 and the fixed scroll wrap 81 so that a compressed fluid may be discharged through it.
To describe the compressing process by the above configuration, the fluid collected in the compressor chamber P of a relatively larger volume formed in the outer portion of the scroll wraps 71 and 81 is moved toward the center by means of the orbiting movement of the orbiting scroll wrap 71. As the fluid moves toward the center, its volume is gradually decreased, thereby increasing the pressure. In addition, the pressure of the fluid is maximum at the center of the scroll wraps 71 and 81, and the fluid gathered at the center is discharged through the discharge port.
The compressor which is operated as above for compressing is already disclosed in U.S. Pat. No. 6,287,099, filed by the same applicant of this application.
The conventional scroll compressor may have a tip seal on the uppermost surface of the orbiting scroll wrap in order to prevent the fluid from being partially leaked outward when the pressure of the fluid is excessively increased.
However, in case of the conventional low pressure scroll compressor to which the above configuration is applied, the tip seal may be melted by high temperature in the compressor chamber P, and the coolant gas may be leaked out of the compressor chamber P.
In addition, if a pressure in the compressor chamber P is excessively increased, the excessive pressure is applied to the Oldham ring seated between the orbiting scroll and the main frame. That is to say, if an excessive pressure is applied to the Oldham ring, the excessive pressure causes excessive frictions between the lower end of the orbiting scroll and the upper end of the Oldham ring and between the lower end of the Oldham ring and the upper end of the main frame, thereby increasing the pressure loss caused by friction.